I'm planning to order a 16" upper, and I am curious is there is any difference between the RRA Mid-Length and CAR versions. Is it just a personal preference, concerning the size of the hand guards, or is there a reliability/cycling issue with the different placements of the gas block & lengths of the gas tube?

I'm guessing there is no reliability/cycling difference between the two, but I figured I'd ask.

If built correctly there isn't a difference in reliability, all should be sized correct as to tubes vs gas ports, buffers, springs etc.... just depending on the setup.

I"d personally take the midlength though, it feels better even if its fugly to me. And it gives a longer cycle for the gas at that point, which means gas port size would be less critical.

Well yes and no...

Given the location where gas is tapped is lower on a mid length, you have less to contend with. Even more so with the rifle length system. Both are easier on parts than the carbine system to start with.

That said the carbine system has been tweaked to the fullest and with the right parts can be just as reliable as any other.

Comparing the midlength and carbine systems set up correctly, shooting the same ammo, the midlength will be easier to shoot but the difference is not great. The greatest comparison is to shoot a rifle then a carbine, the rifle is smoother.

While I have only carbine systems now if I were starting over I'd be going midlength but Colt and LMT don't offer them.

Sabre Defense and Bravo Company do though

Thanks, guys. I was trying to decide between RAA's Coyote Carbine upper or customizing an A4 mid-length upper. I was leaning toward the mid-length, because I could get it with a stainless barrel/Wylde chamber, as the Coyote Carbine only comes with a CM barrel/5.56 NATO chamber.

I think I'll go with the stainless mid-length.

Depending on your intended uses, I would contact White Oak Armament to see what they could do for you in the form of an upper. They have a 16" barrel with the Wylde and 1/7 twist rate that would be my choice with a midlength gas system for a highly accurate hunting type build.

ditto on WOA!

I do realize the shorties have been perfected too TWR, but given everything you have the same length OAL, and a bit less stress, I'd take the less stress every time. Though they are FUGLY to my eye, of course I don't care about looks either.

Another option might be the Armalite M15T upper which is SS and a mid length 20", comes in either Black or Green. I have had very good luck with their products over the years.

http://www.armalite.com/ItemForm.aspx?item=U15A4TB&Category=bce7fa68-373e-4afc-b00e-63fe2c75d131

Ya Jeff, the midlength's with regular handguards are FUGLY but of course we'd put a rail or a tube on them and no one would know the difference....

I actualy have a 16" carbine that has a 9" rail on it and if I ever find the right midlength barrel, I might swap it out. I did like the Kreiger midlength barrel I had but let a thing like money (or lack of) cloud my mind.

I went the Mid length to get the extra length in the handguard. I built my own piston system rifles and like them very much, and as a added bonus get a slightly longer sight radius. If I were to go the CAR route I would want the short barrel, and standard flash hider, but that puts me into the NAF realm and I don't want to go there.